Effect of phototherapy on shear bond strength of resin cements to zirconia ceramics: A systematic review and meta-analysis of in-vitro studies

Evaluation of bond strength of glass and resin-ceramics with laser phototherapy: A systematic review and meta-analysis of in vitro studies

STATEMENT OF PROBLEM

Laser phototherapy has been studied as a surface treatment capable of increasing the adhesion of cement to the ceramic surface. However, the bond strength of glass and resin-ceramics after laser phototherapy is unclear.

PURPOSE

The objective of this systematic review and meta-analysis was to compare the bond strength of glass and resin-ceramics using laser therapy and conventional hydrofluoric acid etching.

MATERIAL AND METHODS

This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was registered in the Open Science Framework (OSF) for in vitro studies. A population, intervention, control, and outcome (PICO) question was formulated: "Does phototherapy promote better bond strength in glass and resin-ceramics than conventional hydrofluoric acid etching?" A literature search was performed in PubMed/MEDLINE, Embase, Web of Science, Scopus, Cochrane Library, and ProQuest databases up to January 2023. The Joanna Briggs Institute critical assessment guidelines for quasi-experimental studies were used for quality assessment. The meta-analysis was based on the inverse variance (IV) method (α=.05).

RESULTS

A total of 6 in vitro studies published between 2007 and 2019 with a total number of 348 specimens were included for qualitative analysis; 1 study had a positive effect. Five of the studies were included in the meta-analysis, which indicated a significant decrease for feldspathic ceramics that received laser phototherapy and lithium disilicate (P=.002; MD: -2.15; 95% CI: -3.53 to -0.77; I²=89%, P<.01) and (P<.01; MD: -2.13; 95% CI: -2.99 to -1.27; I²=82%, P<.01), respectively.

CONCLUSIONS

Laser irradiation as surface etching of glass ceramics does not produce a bond strength equal to that of conventional hydrofluoric acid etching.

Laser Treatment of Fiber Post and Final Push-Out Bond Strength: A Systematic Review and Meta-Analysis

Purpose: This review article tries to answer this question: "What are the effects of laser surface treatment of fiber posts (FPs), compared with other surface roughening methods, on bond strength of cemented FPs?" Methods: Search was carried out in six electronic databases by focusing on defined key words. Related titles and abstracts, up to March 2019, were collected, read, and selected for quality assessments. A total of 2408 articles were included in the study at the initial stage of the searching phase. Results: Finally, seven studies were recognized to be reliable to be reviewed and meta data analysis in the study. All the studies were in vitro with a total of 340 samples. None of the Er:YAG (-0.27, 95% CI: -2.29 to 1.76; p = 0.79) and Er,Cr:YSGG (-0.04, 95% CI: -1.43 to 1.35; p = 0.95) treated samples showed any significant overall mean differences in final push-out bond strength (PBS) compared with the control groups. Conclusions: Laser pretreatment of FP surfaces might not be effective in providing high PBS. FP surface are susceptible to damage of high-level laser irradiation and might show decreased bond strength.

Impact of photodynamic therapy on the push-out bond strength of fiber posts to root dentin: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

This systematic review documents the up-to-date evidence on the efficacy of photodynamic therapy (PDT) on the push-out bond strength of fiber posts cemented to root dentin.

MATERIALS AND METHODS

The focused PICO question was: "What impact does PDT have on the push-out bond strength of fiber posts cemented to root dentin?" This systematic review followed the guidelines and recommendations reported in the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines chart. An electronic search was performed in MEDLINE/PubMed, SCOPUS, Web of Science, and Embase from January 1980 up to and including January 2020. Heterogeneity was calculated for push-out bond strength by means of the Chi-square test and I² statistics. For meta-analyses, if the I² was higher than 50 %, a random effects model was used, otherwise a fixed effects model for I² ≤50 % was applied. A p-value <0.05 was set for significant heterogeneity. Forest plots were computed reporting standard mean differences (SMD) of outcomes and 95 % confidence intervals (CI).

RESULTS

In total, ten studies were included, all of wich demonstrated medium risk of bias. All studies tested the push-out bond strength by means of a universal testing machine with applying a load ranging between 0.5 and 1 mm/min speed. Of the 10 studies, nine (90 %) indicated that PDT had no effect on push-out bond strength of fiber posts to root dentin. Only one study indicated that PDT significantly improved the bond strength when compared with other control groups. The overall mean difference for push out bond strength showed no statistically significant difference between PDT and the control group (SMD = -1.11 [-3.25, 1.02], Z=-1.02, p = 0.305).

CONCLUSION

This systematic review concludes that PDT has no effect on improving the push-out bond strength of fiber posts to root dentin.

Effect of Er:YAG Laser Etching on the Shear Bond Strength and Microleakage of Self-Glazed Zirconia Ceramics

Objective: To investigate the effect of Er:YAG laser irradiation on the shear bond strength (SBS) and microleakage of self-glazed zirconia (SZ) ceramics. Background: SZ is a novel type ceramic; laser irradiation has started to be used in the surface treatment of different ceramics, while SZ has been rarely studied to improve the bond quality. Methods: One hundred twenty blocks (5 mm × 5 mm × 5 mm) of SZ ceramics were produced and split into eight groups following different surface treatments (n = 15): Group A: no treatment; Group B: standard grid processing; and Group C-H: different Er:YAG laser power settings (100, 200, 300, 400, 500, and 600 mJ). Ten blocks of each group received the measurement of SBS and fracture mode analysis, three blocks underwent the evaluation of the microleakage depths, and the other two blocks were observed under the scanning electronic microscopy (SEM). Results: Group F obtained the highest SBS and the lowest microleakage depth without damaging the ceramic surface structure, which was statistically significant compared with the control group and gridding group (p < 0.05), whereas the difference was not statistically significant (p > 0.05) between group E and group F. The results of bonding performance were consistent with failure types and observation of surface characterizations in SEM images. Conclusions: According to the results here, Er:YAG irradiation had effect on surface treatment. In addition, 400 mJ Er:YAG could increase the SBS and decrease the microleakage depth on SZ ceramics without damaging the surface structure.

Effect of laser irradiation on push-out bond strength of dental fiber posts to composite resin core buildups: A systematic review and meta-analysis

BACKGROUND

The bonding of fiber posts (FPs) to composite resin core buildups is a challenge due to limited penetration of resin to the polymeric matrix of FPs. This review article tries to answer this question: "What are the effects of laser surface treatment of FPs, compared to other surface roughening methods, on push-out bond strength (PBS) of FPs bonded to composite resin core buildups?"

METHODS

Searches were run in seven electronic databases with a focus on proper key words. Related titles and abstracts, up to February 2019, were screened, selected, read and subjected to quality assessments.

RESULTS

After the initial search, a total of 2635 articles were included in the study. Finally, 6 studies were reliable enough in methodology to be included. All the studies were in vitro with a total of 359 samples. Er:YAG (-0.05, 95% CI: -2.96 to 2.86; P = 0.97) and Er,Cr:YSGG (0.84, 95% CI: -0.12 to 1.81; P = 0.08) treated samples showed no significant overall mean differences in final PBS compared to the control groups. Moreover, pretreatment with Er,Cr:YSGG laser and sandblasting with 50 μm alumina showed an overall mean difference of -0.42 for PBS (95% CI: -1.23 to 0.39) with no significant differences.

CONCLUSIONS

Laser irradiation of FPs seems to provide no significant increase in PBS values of FPs bonded to composite resin core buildups. Effects of surface treatment of FPs with laser irradiation and sandblasting with 50 μm alumina might be similar in increasing the final PBS, either.